Spark plug



w. E. LYONS Aug. 14, 1934.

SPARK PLUG Filed Sept. 8, 1933 i atentecl Aug. 14, 1934 UNITED STATESSPARK PLUG Willard E. Lyons, Chicago, Ill., assignor to Hart S. Harned,Oak Park, Ill.

Application September 8, 1933, Serial No. 688,592

8 Claims. (Cl. 123-169) improve the appearance and increase theattractiveness thereof.

To the attainment of these ends and the accomplishment of other new'anduseful objects as will appear, the invention consists in the features ofnovelty in substantiallythe construction, combination and arrangement ofthe several parts hereinafter more fully described and claimed and shownin the accompanying drawing illustrating this invention, and in whichFigure 1 is an elevation of aplug of this character constructed inaccordance with the principles of this invention.

Figure 2 is a detail sectional view on an enlarged scale, and as takenon line 22, Figure 1.

Figure 3 is a view similar to Figure 2, showing some of the associatedparts of the plug separated.

Figure 4 is a top plan view of Figure 2, with the binding nutomitted.

Referring more particularly to the drawing the numeral 10 designates theusual shell of a spark plug provided with exterior threads 11' adjacentone end thereof. l

The numeral 12 designates the core of in- 35 sulating material, such asporcelain or glass which is securedin the shell '10 in the usual manner,such as by means of the gland 13.

e The core 12 1s provided with a centrally disposed opening 14therethrough and inwhich opening is arranged the central conductor 15,

whichprojects for a substantial distance-below the coreto-form one ofthe electrodes of the spark gap at the inner end of the plug.

This conductor 15 is held in position by means lof a stem 16 providedwith exterior threads 17 so as to be threaded into the end of the core12.

The conductor 15 is secured to the stem 16 in,

The numeral 20 designates a member which is constructed of a phenoliccondensation prodnot, commonly known as bakelite, and the upper end ofthe stem 16 is threaded into the member 20. The member 20 may beprovided with a recess 21 in its lowerface, and into which recess theflange 18 projects, there being projections 22 extending above the uppersurface of this flange, which are seated in the body portion of themember 20 to hold the member 20 against rotation with respect to thecore 12, and any number'of projections 22 may be provided.

The member 20 is preferably of a diameter substantially equal to thediameter'of the adjacent portion of the core 12.

The stem 16 together with the flange 18 are constructed of any suitablemetal to form a continuation of the central conductor 15;

A second stem 23 constructed of any suitable metal and similar inconstruction to the stem 16,

is provided with exterior threads 24, which are threaded into'the upperend of the member 20,- The stem 231s provided with a flange 25 extend-'ing therearound and of any desired diameter, but is of a diameterconsiderably less than the exterior diameter of the member 20.Projections 26 are'provided on the lower face of the flange 25 which areadapted to be seated in recesses in the upper end of the member 20 so asto hold the member 20 and the stem 23 against relative rotation.

The inner end, 27 of the stem 23 may be reduced in diameter as desiredand when in position and when the flange 25 rests upon the top 0 of themember 20, the extremity 27 of the stem 23 willterminate short of theextremity 19-of the stem 16 to form an air gap 23 therebetween,

and the length of the gap is determined by the spacebetween theproximate extremities of the stems 16;and 23. 3 V I A clamp or bindingnut 29 may be threaded on to the stem 23 and serves as a means forsecuring the high tension cable to the plug.

With this construction it will be manifest that a very simplearrangement will be provided and by reason of the employment of themember 20 constructed of a phenolic condensation product, it is possibleto color the member with any suitable coloring matter and thereby notonly produce a contrast between the core 12 and the member 20, butprovide a rigid and strong construction.

At the same time the parts are so arranged that they may be readilyassembled and the cost of production will be materially reduced.

Furthermore, the member 20 will be a solid construction provided onlywith an opening for 5 receiving the ends of the stems 16 and 23, and theformation of the air gap 28, with the result that a very strong andsubstantial construction will be produced.

While the preferredform of the invention has been herein shown anddescribed, it is to be understood that various changes may be made inthe details of construction and in the com; bination and arrangement ofthe several parts, within the scope of the claims, without departing;from the spirit of this invention.

What is claimed as newisf g 1. A spark plug embodying an insulatingcore, an insulating member ofsubstantiahthickness supported by the endof the core, a central conductor passing through the core and "are saidmember, a

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wi h a en. sa th n the a d. mem er a eis e e sins ea n m ans; betw n heem e and a h o aid eqmiu tcr and. t r. o kns: he. co d c p a d temelse-in t. 10+; tation with respect m said member.

2 A, spark plug embodying an insulating core, Q,,a member constructed ofa phenolic condensa;

ime pr du t upp r edby the end of t eicore. c n r conducto p ssin roughh core and into said member, a centrally disposed. stem assin nthesaidmember andtermi a ing p t i he xtr m t if-s id ondu e to. f rmtherewith a spark gapwithin the said member, n nt rchan n me n between im mber 491. a dste an cQnduc o for oc i a d. member, te an ,cqnduc pr aa st e ati e. tp ov men i mbqqrie aninsul tine cor-a tru d. q ce. h noic e ndensei n were central conductor stem passing through the core aif-4 of he extremity of said conductor stem to 5%:rthe mfatej faces of thecore and said member, one of the contacting faces'being" provided'withaprojection. and the other with a recess receiving the projection tmaintain. the member and core ag'a t'relativerbtation, h f A spark plugembodying an insulating'core', a merri-ber constructed of a phenoliccondensati'on product supported by the end of the core, a centralconductor passing through the core 15- and into saidmember, a centrallydisposed" stem into the said member and terminating short of theextremity of said conductor to se a ate. he tre f. the c re a.

i fiet a a i al lyl ismalstem. the said member, and terminating therewth? afs'park gap 'within the ari me berfafflange on one oflsaid stems,extending q 'ndan'd projecting 'b ween the proxiform therewith a sparkgap within the said member, a circumferential flange on the stem andconductor intermediate the extremities thereof, said flanges contactingopposite faces of said member, and locking means between the flanges andthe adjacent faces of said member for maintaining the member and stemsagainst relative rotation.

5. In a spark plug, a structure providing a threaded stem and acircumferential flange intermediate the extremities thereof, incombination with a core and a member mounted upon the end of the core,the ends of the stem being threaded into the core and the said memberwith said flange therebetween, the contacting faces of the flange andthe said member being provided one with projections and the other withrecesses into which: the projections extend to maintain. the partsagainst relative axial displacement.

6. In a spark plug, a, structure providing a threaded stemand acircumferential flange intermediate the extremities thereof, in.combination with a core of insulatingmaterial, and a capmember ofconsiderable; and substantially uniform thickness having an openingtherethrough, and stem threaded into the ends. of said opening with theproximate ends of thestems in alinement and terminating short of eachother to form anair gap-therebetween and within said member. y

7. In a spark plug, a structure providing a threaded stem and acircumferential flange intermediate the extremities. thereof, incombination with a core of insulating material, a cap member ofconsiderableand substantially uniform thickness having an openingtherethrough, and stemsthreaded into the; ends of said-opening with the.proximate endsof the stems in alinement and terminating short of eachother to form an air, gaptherebetween and w ithin said, member, said capmember; being formed of a phenolic condensation product. V

8.; In a spark plug, a structure providing a threaded stem and acircumferential flange intermediatethe extremities thereof, in combination with a core of insulating material, acap; member of considerable;and substantially uniform thickness having an openingtherethrough, stemsthreaded into the; ends 1 of saidopening withv he; xim e nds o he stemsin s ine: ment and. terminating, short-,of; each other to form an airgap therebetween andwithin said; em e a. um e ntial flan e nt m d a theend of; each of saidstems; and contacting

